Camera model
Canon Dual Pixel CMOS AF|
| Maker | Canon Inc. |
|---|
| Type | On-sensor phase-detection autofocus (PDAF) |
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| Released | 2013 |
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|
| Viewfinder | Yes |
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| Frame coverage | Model-dependent (early implementations ≈ 80%; later models up to ~100%) |
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|
| Video recording | Yes |
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|
| Predecessor | Hybrid CMOS AF / Hybrid CMOS AF II |
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| Successor | Dual Pixel CMOS AF II |
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Canon Dual Pixel CMOS AF is a proprietary autofocus technology developed by Canon Inc., first introduced in mid-2013 with the Canon EOS 70D DSLR. It represents a major advance in autofocus design by integrating fast, accurate phase-detection autofocus directly on the image sensing plane.[1]
Overview
Dual Pixel CMOS AF enables every imaging pixel on a supported CMOS sensor to perform both phase-detection autofocus and image capture. Each pixel is split into two independent photodiodes (side-by-side or top/bottom), allowing the camera to compare light arriving at the two halves for phase detection, and then combine the full signal for image output.[2]
Unlike earlier systems that used separate AF sensors or sparse on-sensor AF pixels, Dual Pixel allows autofocus across a wide central area – about 80% of the frame in early implementations (e.g. EOS 70D) — with later mirrorless models realizing nearly 100% frame coverage.[3]
Technical Background
- On-sensor phase detection: By reading signals from both halves of each pixel, the system computes focus error, direction, and magnitude — just like traditional PDAF — eliminating switching delays between contrast-detection and phase-detection.[4]
- High coverage and speed: Since almost all pixels contribute to autofocus, the system offers millions of potential focus points, yielding smooth and responsive focusing in live-view and video modes.[5]
- Image quality preserved: Because autofocus is integrated at the pixel level rather than using dedicated non-imaging pixels, there’s no penalty to image quality from autofocus processing.[6]
Limitations
- Low-light constraints: Performance may degrade in dim conditions; tracking speed and accuracy depend on sensor sensitivity and firmware algorithms.
- Canon-only system: Dual Pixel technology is proprietary; competing brands use different hybrid autofocus systems.
- Complexity: Advanced versions (Dual Pixel AF II with machine-learning tracking) may require configuration to optimize tracking settings for specific scenarios.[7]
Applications
Dual Pixel CMOS AF is widely used in:
- Live View photography on DSLR and mirrorless bodies, for fast subject acquisition
- Video and cinema use, where smooth autofocus transitions, consistent tracking, and face/eye/animal detection are crucial
- Hybrid workflows benefiting from fast autofocus in both stills and motion imaging [8]
References
